/*
    * Copyright 2008-2010 Digital Enterprise Research Institute (DERI)
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *          http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.deri.any23.validator.rule;
  
  import org.deri.any23.validator.DOMDocument;
  import org.deri.any23.validator.Rule;
  import org.deri.any23.validator.RuleContext;
  import org.deri.any23.validator.ValidationReport;
  import org.deri.any23.validator.ValidationReportBuilder;
  import org.w3c.dom.Node;
  
  import java.util.List;
  
  /**
   * This rule detects the issue of missing Open Graph namespace.
   *
   * @see org.deri.any23.validator.rule.OpenGraphNamespaceFix
   * @author Michele Mostarda (mostarda@fbk.eu)
   * @author Davide Palmisano (palmisano@fbk.eu)
   */
  public class MissingOpenGraphNamespaceRule implements Rule {
  
      public String getHRName() {
          return "missing-opengraph-namespace-rule";
      }
  
      public boolean applyOn(
              DOMDocument document,
              RuleContext context,
              ValidationReportBuilder validationReportBuilder
      ) {
          List<Node> metas = document.getNodes("/HTML/HEAD/META");
          boolean foundPrecondition = false;
          for(Node meta : metas) {
              Node propertyNode = meta.getAttributes().getNamedItem("property");
              if( propertyNode != null && propertyNode.getTextContent().indexOf("og:") == 0) {
                  foundPrecondition = true;
                  break;
              }
          }
          if(foundPrecondition) {
              Node htmlNode = document.getNode("/HTML");
              if( htmlNode.getAttributes().getNamedItem("xmlns:og") == null) {
                  validationReportBuilder.reportIssue(
                          ValidationReport.IssueLevel.error,
                          "Missing OpenGraph namespace declaration.",
                          htmlNode
                  );
                  return true;
              }
          }
          return false;
      }
  }